Sweet baked goods containing starch, water and sweetener are well known. Cakes, breakfast and snack foods, and the like are common examples which are usually formed from flour, water, sucrose and optional conventional additives.
The staling of these food products has long been a most undesirable and seemingly unavoidable phenomenon. Incident to staling, sweet baked goods undergo physical and chemical changes which dramatically reduce their consumer acceptance.
The precise nature of the staling changes is difficult to catalogue completely and precisely. Commonly, however, staling may be said to involve crumb property changes including increases in firmness, crumbliness and harshness of flavor with decreases in desired flavor and in water absorbtion capacity. In addition, crust is often transformed from a dry, crisp and brittle state to one which is soft and leathery.
Apart from the above, staling also involves certain measurable changes of state. More particularly, there may be an increase in starch crystallinity and opacity. These changes are accompanied by variation in X-ray diffraction patterns.
There have been many attempts to retard, reduce or eliminate staling of backed goods. These have included conditions of storage, such as temperature. Further, the effects of various additives have been examined. For example, at Cereal Chem. 54 (2) 150-160 (1977), Kim et al report that small amounts of added pentosans affect the rate of retrogradation of wheat starch gels. None of these investigations, however, has led to a completely satisfactory solution to the staling problem.